SWODY2
SPC AC 091725
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1125 AM CST FRI NOV 09 2007
VALID 101200Z - 111200Z
..NO SVR TSTM AREAS FORECAST...
..SYNOPSIS...
MODELS CONTINUE TO INDICATE A GENERALLY ZONAL SPLIT UPPER FLOW
ACROSS MUCH OF THE NATION DURING THIS FORECAST PERIOD...DOWNSTREAM
OF A STRONG WESTERLY UPPER JET NOSING ACROSS PACIFIC COASTAL AREAS.
AN INITIAL EMBEDDED JET STREAK IS PROGGED TO MIGRATE ACROSS NORTH
CENTRAL PACIFIC COASTAL AREAS...INTO THE NORTHERN INTERMOUNTAIN
REGION...BEFORE WEAKENING AS A MORE INTENSE UPSTREAM JET CORE
GRADUALLY PROGRESSES ACROSS THE MID LATITUDE EASTERN PACIFIC.
IN RESPONSE TO THE EVOLVING UPPER PATTERN...A SURFACE TROUGH IS
EXPECTED TO CONTINUE TO FORM/DEEPEN TO THE LEE OF THE ROCKIES.
AND...A BROADENING/STRENGTHENING LOW-LEVEL WARM ADVECTION REGIME IS
PROGGED TO DEVELOP THROUGH MUCH OF THE PLAINS AND THE
MISSISSIPPI/LOWER OHIO VALLEYS. THIS LIKELY WILL BE ACCOMPANIED BY
A CONTINUING RETURN FLOW OFF A MODIFYING BOUNDARY LAYER OVER THE
WESTERN GULF OF MEXICO SATURDAY/SATURDAY NIGHT.
..EAST OF ROCKIES...
BROAD SCALE MID/UPPER RIDGING IN BOTH THE NORTHERN/SOUTHERN STREAMS
IS EXPECTED ACROSS MOST AREAS FROM THE ROCKIES THROUGH THE
APPALACHIANS. AND...CAPPING LOWER/MID TROPOSPHERIC WARM LAYERS
EMANATING FROM THE MEXICAN/SOUTHERN U.S. PLATEAU REGION ARE EXPECTED
TO INHIBIT CONVECTIVE POTENTIAL ABOVE LOW-LEVEL MOISTURE RETURN
ACROSS THE PLAINS.
HOWEVER...MODELS ARE SUGGESTIVE THAT A WEAK IMPULSE WILL PROGRESS
ACROSS THE UPPER MISSISSIPPI...WITHIN BROADER ANTICYCLONIC UPPER
REGIME. THIS IS PROGGED TO CONTRIBUTE TO A VEERING AND
STRENGTHENING OF THE SOUTHERLY LOW-LEVEL JET...FROM THE CENTRAL
PLAINS THROUGH THE LOWER MISSOURI VALLEY. AND...MOISTENING
ASSOCIATED WITH STEEPENING ISENTROPIC ASCENT TO THE NORTH/EAST OF
STRONGER CAPPING MID-LEVEL THERMAL RIDGE IS EXPECTED TO EVENTUALLY
SUPPORT CONVECTIVE DEVELOPMENT SATURDAY NIGHT. CAPE AND SHEAR IN
THE CLOUD BEARING LAYER COULD BECOME SUFFICIENT TO SUPPORT SOME HAIL
IN SCATTERED STORMS ACROSS THE LOWER MISSOURI/MIDDLE MISSISSIPPI
VALLEY. BUT...THE LACK OF STRONGER UPPER FORCING BENEATH A
GENERALLY CONFLUENT HIGH LEVEL FLOW MAY LIMIT AREAL COVERAGE OF
THUNDERSTORM ACTIVITY...WHILE PROBABLY ALSO LIMITING THE VIGOR OF
THE UPDRAFTS.
..PACIFIC NORTHWEST...
AS COLDER AIR ALOFT OVERSPREADS COASTAL AREAS...ASSOCIATED WITH AN
INLAND PROGRESSING MID-LEVEL TROUGH...DESTABILIZATION COULD BECOME
SUFFICIENT TO SUPPORT A FEW THUNDERSTORMS IN A LINGERING ONSHORE/
UPSLOPE LOW-LEVEL FLOW REGIME TO THE WEST OF THE WASHINGTON
CASCADES.
.KERR.. 11/09/2007
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